Absolute assignment is an unconditional transfer of property or right that leaves an assignor no interest in the assigned property or right. A common assignment that takes place is in relation to debts. A creditor may transfer their right to accept payment from a debtor for money that is owed to a third party. In order for the assignment to be absolute, the whole of the debt must be assigned and the assignment must be unconditional. This protects both the debtor and the third party, in that the debtor is certain of who to pay and the third party is able to sue the debtor for the entire debt in their own name. The English case of Durham Bros v Robertson  1 QB 765 is an example of a case where there was no absolute assignment of a book debt. The assignment was conditional on the third party repaying money to the creditor in order for the book debt to be assigned. As there was a condition precedent for the assignment, there could be no absolute assignment of the book debt.
Pursuant to section 12 of the Conveyancing Act 1919 (NSW) an absolute assignment must:
- be in writing;
- signed; and
- be given to the debtor, trustee or other liable person as notice of the assignment.
Furthermore, the requirement of writing is particularly important in the assignment of real property (land). Pursuant to section 23C of the Conveyancing Act 1919 (NSW) no interest in land can be created or disposed of unless the transfer is in writing and signed by the person who wishes to dispose of their interest.